JPS63104345A - Method for measuring semiconductor device - Google Patents

Abstract

PURPOSE:To easily measure the electrostatic breakdown resistance of an MOSFET by measuring the dielectric strength of an element to be checked, provided on the same pellet of a semiconductor device. CONSTITUTION:A high concentration p<+> type diffused layer 32 is provided in a P-type Si substrate 31, and an oxide film 33 is formed simultaneously in the step of forming the gate oxide film of an MOSFET. The layer 32 is opened to form aluminum electrodes 34, 35. The film 33 of the element to be checked has entirely the same thickness and film quality as those of a gate oxide film of the MOSFET. A voltage is applied across the electrodes 34 and 35, and a voltage for damaging the element to be checked is measured. Thus, the electrostatic dielectric strength of the MOSFET is easily measured.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method for measuring semiconductor devices, and particularly to a method for measuring electrostatic breakdown strength of a semiconductor device having an insulated gate field effect transistor (hereinafter referred to as MOsFET). .

[Conventional technology]

Conventionally, a C charge test as shown in the circuit diagram of FIG. 2 has been known as a method for measuring the electrostatic breakdown strength of this type of semiconductor device. That is, in FIG.
The charged energy is applied to the terminals of the device under test 22 to check whether the device is damaged or not. In this case, the applied energy is expressed as E = (-CV), where C: capacitance of the capacitor 21, V: charged voltage.

[Problem that the invention seeks to solve]

Generally, MOSFETs are said to be semiconductor devices that are susceptible to electrostatic discharge damage. In particular, gate oxide films tend to be designed thinner to improve device performance. On the other hand, the dielectric breakdown voltage BY in the MOS structure is determined by the gate oxide film thickness tox and BV=*j
There is an ox relationship. (K is a proportionality constant.) Therefore, the electrostatic breakdown resistance tends to decrease. In such MOSFETs, elements with poor electrostatic breakdown resistance due to variations in manufacturing process conditions must be removed by checking during the manufacturing process. However, in order to accurately determine the electrostatic breakdown capacity of an element with the conventional measurement method described above, surge energy must be applied until the element is destroyed, and it cannot be applied when measuring all the elements. In addition, when measuring without destroying the element, applying surge energy to the element carries the risk of degrading the characteristics of the element, so the application of energy was kept sufficiently lower than the energy that would destroy it, so the accuracy was very low. There was a drawback.

[Means for solving problems]

The method for measuring electrostatic breakdown strength of the present invention measures the electrostatic breakdown strength of a 9M08FET by measuring the dielectric strength of a check element provided on the same pellet of a semiconductor device.

〔Example〕

Next, the present invention will be explained with reference to the drawings.

FIG. 1 is a conceptual diagram of the measuring method of the present invention. 1 is MOS
B"ET 2 is a check element.

FIG. 3 is a longitudinal sectional view taken along line A-A' of the check element 2 shown in FIG. High concentration P type diffusion layer 3 on P type Si substrate 31
After forming the gate oxide film 2, a oxide film 33 is formed at the same time as the gate oxide film of the MOSFET, holes are opened in the P-type diffusion layer 32, and aluminum electrodes 34 and 35 are formed. The oxide film 3:3 of such a check element has exactly the same thickness and film quality as the gate oxide film of the MOS1i'ET, and has the same thickness and quality as the gate oxide film of the MOS1i'ET, and
- By applying a voltage between 35 and measuring the voltage at which the check element breaks down, the electrostatic breakdown capacity of the fiMOSFET can be estimated with high accuracy. FIG. 4 shows an example of the correlation between the dielectric breakdown voltage BV of the check element and the electrostatic breakdown 1-HEESD of the MOSFET.

〔Effect of the invention〕

As explained above, the present invention has been developed by measuring the dielectric strength voltage of a check element made of 1-6M08G using an oxide film formed in the same process as the gate oxide film of MOSF'ET and having a very thick film quality. ``It has the effect of being able to check the static and mechanical breakdown resistance of a MOSFET without damaging the VL or causing characteristic deterioration of the ET.

[Brief explanation of the drawing]

FIG. 1 is a conceptual diagram of a method for measuring a semiconductor device according to the present invention. 1...MOSFET, 2...Check element Figure 2 shows a conventional method for measuring semiconductor devices. 21... Capacitor, 22... Element to be measured. FIG. 3 is a vertical sectional view taken along the line A-A in FIG. 31... PiSi substrate, 32... High concentration P type diffusion layer, 33... Oxide film, 34.35.
...Aluminum electrode Fig. 4 Example of correlation between dielectric strength voltage BV of check element and electrostatic breakdown energy EEsD of MOSFET. ′斥、; Agent: Patent Attorney Uchihara Sho. 1.、Ha No.
2 ■

Claims (1)

[Claims] By forming a MOS structure check element having an insulated gate field effect transistor and having an oxide film formed in the same process as the gate oxide film, and measuring the dielectric strength voltage of the check element, the insulated gate electric field can be measured. A method for measuring a semiconductor device, characterized by measuring the electrostatic breakdown resistance of an effect transistor.